1. Field of the Invention
The present invention relates generally to commercial cooking griddles and, more particularly, to a composite cooking griddle having a thin cook surface layer, preferably of stainless steel, that intimately contacts a thicker heat conductive core layer of copper or aluminum by means of a vacuum.
2. Description of Related Art
In commercial cooking griddles there is a long-felt need to provide a cook surface with a fast thermal recovery time when cooking, for example, frozen hamburger patties. In conventional steel plate griddles, areas of the cook surface occupied by the frozen patties experience a decrease in temperature which requires a prolonged recovery time to reach a desired temperature for proper cooking of the meat. This is caused by the fact that steel does not possess a relatively high coefficient of thermal conductivity. When the hamburger patties are flipped to cook the other side, the patties are usually placed in areas previously occupied by a frozen side and oftentimes are exposed to less than ideal cooler temperatures for proper cooking. Thus, in conventional fast food-type commercial griddles, the throughput time is extended. If the cooking time is not increased, there is a real danger that the meat is not thoroughly cooked, resulting in a health hazard due to the possible presence of E. coli bacteria.
An ongoing effort to improve thermal recovery of commercial cooking griddles is evidenced by my U.S. Pat. No. 6,109,504 which utilizes a thick, thermally conductive core layer of copper explosion bonded and rolled with a cook surface of stainless steel. This has proved to be very workable from a commercial cooking standpoint since the copper core offers a much faster heat recovery than does the typical commercial griddle plate made from carbon steel. Unfortunately, the explosion bonded and hot rolled griddle plate of my aforementioned patent is relatively costly to manufacture.
The present invention solves the problems heretofore encountered in the prior art by providing a composite griddle plate having a core of high conductivity metal which transfers heat to an outer cook surface layer of a different metal, much like a roll bonded composite, but at a much lower cost.